Pneumatic rock-drill.



E. vALIENlfOl-'FR v PNEUMATIC ROCK DRILL. APPLIoATIoN FILED DEG. 26,1911.

Patented Nov. 25, 1913.

zpeizor: v

UITED- STATES PATENT onirica..

EDUARD ALTENHOFF, OF OBERHAUSEN, GERMANY.

PNEUMATIC ROCK-DRILL.

Specification of Letters Patent.

Application led December 26, 1911. Serial No. 667,911.

To all whom t may concern.'

Be it known that I, EDUARD ALTENHOFF, a subject of the King of Prussia, Germany, residing at Oberhausen, Germany, have invented a new and useful Pneumatic Rock- Drill, of which the following is a specification. f

When pneumatic rock-drills with automatic feed are t0 satisfy all reasonable demands, theyA must coperate with their guide-bar in such a mannert-hat a regular feed isassured, even when the axis of the drill-ho-le deviates up to 90 .above or below the horizontal, and besides this, the guidebar must not only offer the'possibility of directing the drill to any point of the crosssectional area of the tunnel, gallery and the like to be constructed, but must also per` mit the axis of the drill-holes to form different angles with the longitudinal axis of said tunnel, galleryandfthe like. To obtain this, the connection between the rockdrill and the guide-bar must be based upon such a principle, that the feed of the rockdrill can be suitably increased or'diminished in order to adapt itself readilyv to any direction of the drill-holeor hardness of the rock. This is necessary for the reason, that in the first instance. the weight of the rockdrill influences the work of the drill in a different way when a drill-hole is directed upwardly than when directed downwardly, as will be readily understood; whereas in the second instance the reaction ofthe drill will be more powerful on hard rock than on the softer varieties thereof. To these difficulties must be added the inconvenience caused by dirt and grit unavoidable in rock-- drilling, which Will clog all parts of the drillingv apparatus and will 'of course be found particularly trying and inconvenient on the aide-bar. The connection between rockdrill and guide-bar must therefore be designed with a view to eliminate the drawbacks originating from a dirty and perhaps greasy guide-bar to enable the feed-mechanism' to take at all tim'es and under the most trying conditions give afsure grip on the guide-bar. i

vThe object `of my present invention is to satisfy these/demands which I accomplish by arranging upon the guide-bar carrying the rock-drill a clamping-shoe which takes hold" of said guide-bar without the least delay as soon as the rock-drill tries to escape backward upon delivering the blow. To

4partly generated by said Anent. advance of the latter.

` bar.

one hand this backward motion of the rockdrill itself and insert on the other hand between the latter and said clamping-shoe, an elastic element adapted to retain these parts at all times in touch one with another. However, in order to utilize any suitable part of the forward motion of the rock-drill, elast-ic element, partly by a clamping-lever carryingthe lat.- ter, and partly by the power generated by the driving-medium employed to retract piston and striking-pin while acting upon the forward annular cylinder-cover as far as this is made possible by the inertia of said piston and its striking-pin,l I provide said clamping-shoe with adj listing-means adapted to appropriate 4any desirable part of the for'- ward motion of the rock-drill for a perma- The clampingshoe employed must of course accommodate itself-to the shape of the guide-bar that supports it, which in turn may be of t-he simple v ariety usually secured by a wedge in the rock, or it may be executed as a compound'- The latter makes it possible, by employing a boring-bracket, for the drill to notonly be directed to any point of the crcsssectional area of the tunnel or gallery to be driven forward but the direction of the drill-holes.can also be made to run atdifferent angles to the axis of such tunnels, galleries, etc.

In the accompanying drawings z-Figure l is an eleva-tion partly in section of a pneumatic rock-drill constructed in accordance with my present invention and showing a clamping-shoe which operates in a channeled guide-bar. Fig. 2 is a similarjview of the pneumatic rock-drill provided with a clamping-shoe as well as with a clampingring simultaneously operating upon a guide* bar carried by an adjustable boring-bracket. l

accomplish this without fail I employ on the Fig. 2 is a side Aview partly in section vof 100 the clamping ring and adjoining parts. Fig. 3 is another similar view of the pneumatic rock-drill sustained by a guidesbar carried by a .boring-bracket whose adj ustable arm is bent to form an obtuse angle to permit of 'drill-holes being made to run at different angles to the axis of the tunnel, gallery or the like to be driven into the rock. Fig. l is an end View of the clamping shoe of Fig. l; Fig.I 5 a detail of the adjusting screw and coperati'ng parts; Fig. 6 an end View thereof; F ig. 7 a detail of the friction rock 3 by means of the wedge 2 which slides 'l upon the sloping base 4 arranged within the channel of said bar. The pneumatic rockdrill 5 oijany suitable construction is connected with the guide-bar 1 by means of the foot 6 and foot or abutment 7 of Y- shaped form which feet are securely attached to said rock-drill by the aid of the side-rods 8. Since the feet only. permit of the rock-drill being moved back and forth upon the guide-bar lit may be used either in a standing or in a hanging position.

The channel 9 of the guide-bar 1 serves for the reception of the clamping-shoe 10 the sides of which are of course slantedto suit the inclined inner faces of the cheeks 11 and 12, Fig. 4. The clamping-shoe 10 carries on its rear-end two lugs 13 between which the clamping-lever 14 is rotatably supported by the pin 15. To the upper end of said lever is secured a spring 16 which serves as a cushion and always remains in contact with the handle 17 of rock-drill 5. The lower-end of the clamping-lever 14 is forked to straddle the clamping-shoe as Well as the guide-bar and' carry the friction-block 18 which is supported by the pin 19. The hole 20 serving for the reception of the latter is so arranged that the four friction-faces of said block are arranged at dierent distances from the center of the hole 20 and can thus be brought consecutively into contact with the underside of the guide-bar as the wear and tear of the work may require this. The friction-surfaces of said block may be roughened in any suitable manner ify this' should be deemed necessary.

In order to regulate the feed of the rockdrill to suit any particular direction of the drill-hole or hardness of rock an adjustingscrew 21 is arranged in the extension 22 of the clamping-shoe 10 and can be manipulated by the weighted lever 23. The latter is rotatably attached tothe head 24 of the screw 21 by means of the forked plug 25 rotatably but not slidingly held in said screwhead. The lever 23 is further provided with a nose26 which can be consecutively inserted into the radial slots 27 of the-head 24. To prevent the lever 23 from rotating and thus leaving the slot the head 24 is provided with a scmicircular groove 28 and the 'nose 26 rock-drill may be.

with a hole 29 so that when the groove 28 and the hole 29 coincide a split-pin 30 attached to a small chain 31 may be inserted into said hole and thus retain said lever locked no mattei' what the position of the l When released by the operator, lever 23 will by its own weight permanently maintain the position shown I guides.

in Fig; 1, thus `preventing an accidental' change in the adjustment of screw 21.

The operation is as followsz--It is a well knownV fact that the rock-drill rebounds backward when the drill 32 receives the blow. At the beginning of this backward motion of the rock-drill the handle 17 of the latter' commences to tension the spring 16 which up to this moment was onl suiiiciently tensioned to keep rock-dri and clamping-shoe in feeling contact with each other. The spring 16 will be gradually compressed and the lever tilted when the` resistance of the spring has reached a point`V to transfer the pressure exerted upon 1t by the handle 17 fully to the lever 14. At the moment this takes place the lever 14 swings on the pin 15 and thus resses the frictionblock 18 against the un erside of the bar 1 and simultaneously presses the c amp-` ing-shoe from above into the channel 9 of the guide-bar. The friction created herebyide- B5 suffices to arrest the rock-drill insta'nta-I neously. Care must however be taken to pre-j'` vent the pressure-components from becoming powerful enough to bind the clampintgi shoe too hard in the channel. This ma readily prevented by giving the inner aces of the cheeks 11 and 12 the proper inclination. While arresting the backward'motion of the rock-drill energy was stored up in the spring on the clamping-lever, which ener manifests itself in throwing the 'rock-drill. p forward-in the opposite direct1on. In this 100 action said spring 16 is aided by the action of the compressed air which in the meantime has been admitted to the front side of the piston (not shown) in order to retract said piston and the striking-pin carried thereby.` The wholeforce thus generated will however not come hereby under consideration, but simply that part thereof due to the inertia of the piston and its striking-pin and-the friction caused by the latter 1n its If the whole forward travel of the rock-drill is represented by the value 10, and that part thereof destined for the actual forward feed of the rock-drill by the value a, then the remainder will be :fw-a. If this part be represented by the value b then it is evident that during this part of .travel the clamping-shoe must remain at rest. To vary the values a and b to suit any given conditions the distance between the extension 22 and the abutment 7 must be altered accordingly z'. the pointof the screw 21 must approach the extension 22 when the value b is to be increased and recede therefrom when the value a is to be increased. The s ring 16 remains readily in contact with tlie handle 17 during this adjustment since practically only very small lineal displacements of the clamping-shoe need be considered. In view of the fact that the distance traveled backward by the rested and tite latter has started to accomi lish its forward travel :un the clamping-shoe will remain at rest until the abut- 'inent 7 strikes the point of the screw 21 z'. e.

after the value b has been attained the rockdrill and clamping-shoe will proceed simult-aneously until both come to a stand-still. It

is therefore evident that the value a c'an be iXed by varying the value b. As in the meantime the driving-medium has been led again behind the piston of the rock-drill the latter will move again to the right until the handle 17 -will tension the spring 16 anew and thus compel the lclamping-lever 14 to operate the clampinglshoe 10 again. The rock-drill will thus be arrested.lagain, but at a distance equal lto the value a. nearer to the rock 2 or what amounts to the same in front of the po-int where it was arrested at the preceding blow. After this the rockdrill will be thrown forward again and after having traveled over its way w-fa-i-b be thrown-back again with the result ,explained above. This play of the rock-drill will con'- tinue until the driving-medium is shut oil' and the operation of the drill 32 ceases.

Exactly the same operations will take place in the pneumatic rock-drills 5 shown in Figsk 2 and 3 notwithstanding the fact that the clamping-shoes are somewhat different in shape to` the one shown in Fig. 1. In the first place the guide-bar 33 of Fig.`2 is not Weight of the rock-drill do the rest.

channeled neither secured directly in the rock Abut carried by an arrn 34 ofI a boringbracket 35', the plug-member 36 of which is secured in the rock by a wedge 37.l `Member 36 is provided with a head 36 against which arm 34 is held by a wedge or key- 38 engaging a corresponding,r slot formed in the protruding end of said member. To securely hold the guide-bar 33 it suffices to slip the eye of the latter over the arm 34 and let the Keys or binding-screws may of course be einployed if deemed necessary. This simple connection of the guide-bar with said bracket already suffices to permit of holes being drilled on four radial lines by simply altering the position of the plug-members 36. ln castthis should not suffice the key 38 is eased sntliciently to swing the arm 34 into the desired position and there secure it again by driving the key 38 home. The feet 6 and 7 employed in Fig. 1 are here replaced by other elements the one by the clampingring 39 andthe other by the extension 40 of the cylinder-cover 41. The elanlipingshoel 42 is in this instance arranged beneath-the guide-bar 33 and the clamping-leverl 43 thereof is provided with a clamping-foot 44. The clamping-lever 43 is U-shaped inI crosssection like the clamping-lever 14 in Fig. 1 and carries, like the latter, a spring 45, besides which it is provided with lateral lidelugs 46. In the extension 47 of the camping-shoe 42 an adjusting-screw 48 is ariranged the extension 49 of which passes `through thes'aid cover extension 40. This screw may be adjusted by means of the, hexagonal-shoulder 50 and secured in any given g` position by the check-nut 51. 'The clamp- `ing-ring 39 is losely seated upon the pintle 52 of the boss 53 in such a manner that it- 4will be caused to grip the guide-bar 33 during the backward motion of the rock-drill while trying to turn clock-wise. The corner 54 will hereby try to penetrate'into the top` face of said guide-bar whereas the corner 55 will try to do the same in regard to the bottom-face thereof. The result obtained hereby is, that the clamping-ring 39 will easel the gripping-work 'of the clampingshoe 42 and thus aid the'latter. The force required by the clamping-ring lfor doing its work is furnished by the weight of the rockdrill. The pin' 56 prevents the clamping? ring 39 from slipping from the pintle 52.

Since the working of the elamping-shoe 42v is identical with that of the clamping-shoe 10 of Fig. 1, it only remains to direct attention ,to act that on tilting the clampinglever through the instrumentality of theI backward-motion of the rock-drill, the clamping-foot 44 will be pressed against the top-face of the clamping-bar 33l and thereby draw the'inner face of the clamping-shoe 42 against the bottom-face of theV guide-bar. The inner face of the clamping-shoe may be roughened in any manner, if so desired. It is evident, that the guide-bar 1 of Fig. 1 might lbe employed in cpnnection with the boring-bracket` 35, since all that is ,necessary for this purpose is to provide it with an eye adapted to beslippe'd over the arm 34.

'.lhe pneumatic rock-drill shownin Fig. 3 is mounted upon the guide-bar 59 by the aid of the fool-.'57 and the eye 58.- The guidebar itself is mounted in this instance on the bent arm 60-.of a boring-bracket 6.1 in all other respects similar to the one shown in Fig. 2.A IThe bent arm 60 can be .secured to the plug-member' 36 in any desired direction by means ofthe nut 62 and offers this advan- -tage over the straight arln 34 that by a simple face-about turn, said. arm, guide-bar and everything carried by it may be brought into the position indicated by dotted lines in Fig. 3. This peculiarity may be advantageously appropriated for retaining the intended cross-sectional area of the tunnel,`

, sectional area and cross them more or less as their depth increases. The result will be, that after the charge has been ignited and the undermined part of the rock has been blown away said area will be'rather increased than decreased, or in other words, that by means of this arrangement all unnecessary manual labor will be avoided.

In the modification illustrated in Fig. 3,

the clamping plate or shoe 64 carries a two arm lever comprising a lower arm 65 and an upper bent arm 67, 70, said lever combining the parts 39 and 43 shown in Fig. 2. Plate 64 is roughened at its lower side and has opposed lateral recesses 66 (Fig. 8) which serve for retaining said plate in position. The parts are assembled by slipping plate 64 in an upright position into a corresponding opening provided in the lower lever arm (S5-and bythen giving said plate a quarter turn. AThe section'67 of the upper lever arm extends in substantial parallelism with bar 59, while bent section projects upward at right angles to sect-ion 67. A slot 68 of section 67 receives the stem 69 of eye 58, and section 70 carries arebound spring 71 and lateral guides 72. To arm 65 is secured by bolts 74 a check plate 73 which may be adjusted relatively to guide bar 59 by means of a'screw 75 having a squared end 76. The latter enters into -a slot 77 of the plate 73-and is held thereby in such a manner. that it cannot be rotated so that to advance the plate 73 it becomes necessary to unscrew the bolts 74, lift the plate 7 3 and replace these parts again after the screw has been set. To ease thework of the screws 74 the underside of the plate 73 may be roughened as indicated in Fig. 3. A spring 7S aids the lever 65, 67, 70, in retaining its most advantageous position on the guidebar. The regulation of the feed is accomplished by means of the set-screw 79 which is held by eye 8O secured to arm 67 and can be secured after each adjustment by means of the check-nut 81.

. lhen on moving backward the rock-drill 5 co-mes into contact with the spring 71 and thus tensions it until it can push the arm 70 backward, lever`- 65, G7, 70 will swing on the edge 8:2 of lever arm 65 so thatthe upper edge Stof check plate 73 will be forced againsty the lower side of bar 59. ln this way shoe 64 will be clamped to this bar' whenever drill 5 rebounds.

From the foregoing it will be manifest that the backward motion of the rock-drill of any kind may 'be utilized to block its own way by compelling the clamping-shoe to grip the guide-bar, that further a predeterminable fraction of the forward motion `of the rock-drill can be utilized for the forward feed of the rock-drill and that the backward motion of t-he rock-drill may be brought to a close when the latter reaches a point which lies in advance of the arrestingpoint reached at the preceding blow to the extent equal toits feed.

l. A device of the character described, comprising a bar, a clamping shoe movable along said bar, a clamping lever pivotally connected to said shoe, a rock drill slidably supported by said bar, means for intermitently advancing said drill, a rebound spring intermediate said lever and drill, and means on said lever for locking the clamping shoe to the bar.

2. A devieeof the character described, comprising a bar, a rock drill adaptedto be intermittently advanced along said bar and havin an abutment, a clamping shoe movable a eng the bar, a clamping lever pivotally connected to said shoe, a rebound Spring intermediate the drill and lever, and drilladvancement adjusting means movable with the shoe and adapt-ed to be engaged by the drill-abutment.

3. A device of the character described,

comprising a bar, a rock drill adapted to be intermittently advanced along saidbar and having an abutment, a clamping shoe movable along the bar, a clamping lever pivotally connected to said shoe, a friction block carried by the lever and adapted to engage the bar, a rebound spring intermediate the drill and lever, and an adjusting screw tapped into the shoe and adapted to engage the drill-abutment.

4. A device of the character described, comprising a bar, a rock drill adapted to be intermittently-advanced along said bar and having an abutment, a elan'lping shoe movable along the bar, a clamping lever pivotally connected to said shoe.l a friction block carried by the 'lever -and adapted to engage the bar, a rebound spring intern'xediate the drill and lever, an adjusting screw ltapped into the shoe and adapted to engage the drill-abutment, a slotted head on said screw, and a swinging gravity lever pivoted to said luad and adapted to engage the head-slots.

Signed by me at Barmen, Germany, this 14th day of December i911.

EDUAlll) AL'FIGN'ITOFIF. [`r..s.l l/Vitncsses:

lll-:LEN Nu'ruu,

A. Nunen. 

